Lumpy Idle

Okay so I'v had my micra for a few years now but it is only a competition car so it sees very little mileage usually at high rpm. I had an overheating problem so tried a few thermostat and eventually had to get the head skimmed, very lightly. After it came back from having this done it never seemed as responsive on the throttle, not so noticeable in a road car but extremely so in mine. (Wasnt such a big problem when I was starting as i didnt mind where I finished however now I want to finish well and am being let down by the car) I struggled through for a year or so changing Lambda sensors, air flow meters and I even got the inlet manifold gasket changed. Its a 1348 cc Coilpack engine so cant change the timing and cannot reprogram it at nissan.

Symptoms: Lumpy Idle, (will post video when i get it back), extremely unresponsive. Nissan said it could be a burnt valve or a coilpack breaking down however my local garage reckoned it was a gasket. A fella i compete against says its unlikely to be a burnt valve as his was and sounded slightly different.

Any help greatly appreciated I'm getting fed up off it. Thanks Paul
No cant change it on coil pack model. Someone suggested a stretched timing chain? Anybody heard of this problem its expensive to fix and i dont want to if it wont fix it... Thanks


1st Micraversary!
If the head was changed I would re-examine the camshaft timing to be sure it isn't a tooth out or something. While you've cracked it open you can check for excessive play in the top (cam) chain. Applies irrespective of dizzy/coilpack.